Someone asked me something interesting regarding what official releases need to be owned before getting the Despecialized Editions.

Apparently, some countries like Hong Kong and the Philippines had DVD-only versions of the 2011 Special Editions which were the basis for the Despecialized Editions.

She asked me if one is legally allowed to download the Despecialized Editions if she owns the 2011 Special Editions on DVD but not Blu-ray.
And if so, is she allowed to download any version or just the DVD5 version?

And, if she bought the digital releases but only in SD, is she allowed to download any version of the Despecialized Edition or only the DVD5 version?

Please give me answers for my friend who wants to dip into the Despecialized Editions.

Your friend is seemingly mistaken - the blu rays of the Original Trilogy are available in Hong Kong, and other places across Asia. There is also a regional version with Traditional Chinese, Korean, Thai subtitles:-

‘Remember, as with any fan edit, YOU MAY ONLY DOWNLOAD THIS PROJECT IF YOU ARE A LEGAL OWNER OF THE OFFICIAL SOURCE. For Harmy’s DE project, this means YOU MUST OWN AN OFFICIAL HD RELEASE for each respective film (i.e. Star Wars Episodes IV, V, & VI), such as the official Blu-ray Disks or digital purchase.’